I'm sorry they lost their daughter, reportedly as a result of texting while driving, but that doesn't keep me from calling them dumb and silly for lobbying for a state ban on texting while driving...

There are three groups of people. One group is made up of people who don't text at all, whether in a car or sitting on a park bench. They don't text while driving anyway, so a ban would have no effect on them. A second group is comprised of people who, like this poor girl, know texting while driving is dangerous, but unlike her daughter, aren't texting while driving. A ban would have no impact on these folks either. The third group is comprised of people who don't think texting while driving is dangerous (if not to everybody, at least not to them). I include in this last group people like the poor girl who acknowledged the danger but did it any... in the end, actions speak louder than keystrokes.

What percentage of this last group would stop texting while driving because there's now a law that prohibits doing so?

Yeah, pretty close to zero. There really isn't much of an intersection between the group of people who think an activity is safe and those who will stop the activity because of a law that they are ever likely to be cited for.

In other words, the law will have no impact whatsoever on the number of people who are killed or injured as a result of texting while driving.

And anyone who doesn't realize this... or who realizes it and still pushes for it... is dumb.